Drivers of geophagy of large-bodied Amazonian herbivorous and frugivorous mammals

Mineral licks, critical for the survival of many large-bodied mammals in the Amazon, serve as keystone resources that influence the behavior and ecological dynamics of these species. This study presents the most comprehensive analysis to date on the drivers of geophagy—the consumption of soil by animals—at mineral licks in the Peruvian Amazon. Using a combination of camera traps and soil analyses from 52 mineral licks, we examined the visitation patterns of six large-bodied mammals: the black agouti (Dasyprocta fuliginosa), paca (Cuniculus paca), collared peccary (Pecari tajacu), Brazilian porcupine (Coendou prehensilis), lowland tapir (Tapirus terrestris), and red howler monkey (Alouatta seniculus). Our results reveal that mineral licks provide essential nutrients, particularly sodium (Na), which may be deficient in the diets of frugivorous species such as agouti, paca, and red howler monkey, supporting the mineral supplementation hypothesis. Conversely, the toxin adsorption hypothesis, which posits that animals consume soil to mitigate dietary toxins, was most strongly supported for the herbivorous Brazilian porcupine. The omnivorous collared peccary and the mixed-diet tapir exhibited complex interactions between soil characteristics, suggesting that both mineral supplementation and toxin adsorption play roles in their geophagy. This study highlights the importance of mineral licks for the conservation of Amazonian mammals, emphasizing their role in supporting biodiversity by providing critical nutritional resources that enhance species fitness and ecological resilience. Our findings underscore the need for the protection of these sites, which are integral not only to the survival of individual species but also to the health of the broader Amazonian ecosystem.矿物舔食点（mineral licks）是亚马逊流域众多大型哺乳动物生存的关键依托，作为影响这些物种行为与生态动态的核心资源。本研究针对秘鲁亚马逊流域矿物舔食点处的食土行为（geophagy，即动物食用土壤的行为）驱动因子展开了目前最为全面的分析。研究依托52处矿物舔食点的红外相机陷阱（camera traps）监测数据与土壤分析结果，对6种大型哺乳动物的到访模式展开了调研，分别为：黑刺鼠（Dasyprocta fuliginosa）、斑豚鼠（Cuniculus paca）、领西猯（Pecari tajacu）、巴西豪猪（Coendou prehensilis）、低地貘（Tapirus terrestris）以及红吼猴（Alouatta seniculus）。研究结果表明，矿物舔食点可提供关键营养物质，尤其是钠元素（Na）——而食果动物如刺豚鼠、斑豚鼠与红吼猴的饮食中往往缺乏该元素，这一结果支持了矿物质补充假说（mineral supplementation hypothesis）。与之相对，针对植食性巴西豪猪的调研结果则最有力地支持了毒素吸附假说（toxin adsorption hypothesis），该假说认为动物通过食用土壤来缓解膳食中的毒素。杂食性的领西猯与食谱混合的低地貘则表现出与土壤特性间的复杂关联，这表明矿物质补充与毒素吸附这两种机制均对它们的食土行为存在影响。本研究凸显了矿物舔食点对亚马逊哺乳动物保护的重要意义，强调其通过提供关键营养资源以提升物种适合度与生态韧性，进而助力生物多样性维持的核心作用。研究结果同时强调，亟需对这些位点开展保护——它们不仅是单个物种存续的必要依托，更是维系整个亚马逊生态系统健康的关键组成部分。